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A155141
Primes p such that both p-+4 are squarefree.
5
2, 3, 7, 11, 17, 19, 37, 43, 47, 61, 73, 83, 89, 97, 101, 107, 109, 127, 137, 163, 181, 191, 197, 199, 223, 227, 233, 251, 263, 269, 277, 281, 307, 313, 317, 331, 349, 353, 389, 397, 431, 433, 439, 443, 449, 457, 461, 467, 487, 523, 541, 547, 557, 569, 577, 587
OFFSET
1,1
MATHEMATICA
<<NumberTheory`NumberTheoryFunctions` lst={}; Do[p=Prime[n]; If[SquareFreeQ[p-4]&&SquareFreeQ[p+4], AppendTo[lst, p]], {n, 6!}]; lst
Select[Prime[Range[150]], AllTrue[#+{4, -4}, SquareFreeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jun 15 2016 *)
PROG
(PARI) lista(nn) = forprime(p=2, nn, if (issquarefree(p-4) && issquarefree(p+4), print1(p, ", "))); \\ Michel Marcus, Jul 06 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved